clocksource: mct: add support for mct clock setup

Add support for mct clock lookup and setup to ensure that the mct
clock is has been turned on.
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

drivers/clocksource/exynos_mct.c

@@ -479,7 +479,7 @@ static struct local_timer_ops exynos4_mct_tick_ops __cpuinitdata = {
 
 static void __init exynos4_timer_resources(struct device_node *np)
 {
-	struct clk *tick_clk;
+	struct clk *mct_clk, *tick_clk;
 
 	tick_clk = np ? of_clk_get_by_name(np, "fin_pll") :
 				clk_get(NULL, "fin_pll");
@@ -487,6 +487,11 @@ static void __init exynos4_timer_resources(struct device_node *np)
 		panic("%s: unable to determine tick clock rate\n", __func__);
 	clk_rate = clk_get_rate(tick_clk);
 
+	mct_clk = np ? of_clk_get_by_name(np, "mct") : clk_get(NULL, "mct");
+	if (IS_ERR(mct_clk))
+		panic("%s: unable to retrieve mct clock instance\n", __func__);
+	clk_prepare_enable(mct_clk);
+
 	reg_base = np ? of_iomap(np, 0) : S5P_VA_SYSTIMER;
 	if (!reg_base)
 		panic("%s: unable to ioremap mct address space\n", __func__);